1. Field of the Invention
The present invention relates generally to a stator of a rotating electric machine, such as a motor, and a method of manufacturing the stator. More particularly, the invention pertains to a wire-connecting structure for a distributed winding configuration of traverse wound coils.
2. Description of the Background Art
A stator of a rotating electric machine includes a stator core, coils wound on the stator core and insulators installed in multiple slots in the stator core for insulating the coils from the stator core.
The stator core has a cylindrical structure made of laminated thin steel plates. The multiple slots extending parallel to a central axis of the stator core are formed therein at specific intervals along an inner circumferential direction of the stator core, the individual slots opening to the interior of the stator core. When installing the coils in the stator core, a laminated core assembly is stretched in a beltlike form to make the width of each slot larger than the width of coil conductors so that the conductors having the larger width can be fitted into the slots. After the coils have been fitted into the slots in this way, both ends of the beltlike laminated core assembly are positioned against each other to form an annular structure and joined together by welding, for example, to complete the stator core.
A conventional form of winding the coils is a wave winding structure in which coil ends of each conductor are folded back outside axial end surfaces of the stator core. To realize efficient use of internal spaces of the slots, two sets of coils are wound at intervals of a specific number of slots in such a way that two conductors constituting a conductor pair are disposed alternately in inner and outer layers in a depth direction of the slots, constituting a three-phase distributed winding configuration. Leads of the three-phase coils are connected to terminals of the three-phase configuration that are connected to an external electric circuit as shown in Japanese Laid-open Patent Publication No. 2001-211584.
According to the Patent Publication, jumpers for connecting the coils of each set in series are connected at regular intervals, or the conductors in the same layer are joined to each other, at one axial end of the stator core to improve efficiency of wiring work. For this reason, the leads of the coils are disposed at locations separated from one another along the circumferential direction of the stator core. In this structure, it is necessary to route around the leads from their separated locations for properly connecting the leads, requiring a large space in the circumferential direction.